Attached are trends over an hour where the BS HEPI actuators were driven individually to look for limits.  The plot is likely only useful for me but it does contain the local sensors and the OUTPUT drive and the Z location_mon.  I've zoomed into the X-axis of each corner during that corner's drive, hence the screwed up DV x axis.  Anyway, it shows some clipping and limits but again mostly for me.  I drove sine of various amplitudes.

In the end the IPS should have good signal to +-1mm but the signal is better the closer it is to zero.  The mechanical limit of the Actuator is design to be 1.375mm and the sensor gap is 1.625mm.  So best to have the IPS operating at zero but you can't just zero it out where you sit.  If the platform has sagged for some reason you can get close to the mechnical limits and if you muck about too much with the sensor position, the sensor can be put in jeopardy.

The take away is the following:

V1--Appears to be hitting a mechanical limit at +22K (~0.8mm) and is reaching the IPS limit at -32k counts.  Suggests the actuator could be lowered and/or have the IPS rezero'd, but really, the range is fine.

V2--With the sensor centering I did yesterday, V2 is moving freely for +- 1.1mm, plenty of range.

V3--This sensor is showing some sign of clipping at 0.4mm but I think these signs are just showing how the V4 limits impact the other (mainly corner 1 & 3.)  Should repeat after V4 is fixed.

V4--Despite the closeness of the mechanical stop on this corner (see last photo on alog 40171) the corner is still moving about 0.8mm.  This test isn't good for performance evaluation and I'd still like to do the Actuator reset to make sure we are not too close.

Closing WP 7297